The efficacy of male condom use in preventing herpes simplex virus-2 transmission among HIV-1 and herpes simplex virus-2 serodiscordant couples varied by gender, according to recent findings.
“We found condoms reduced the per-act risk of [HSV-2] transmission by 65% from women to men and by 96% from men to women,” Helen Rees, MD, executive director of the Wits Reproductive Health and HIV Institute, University of Witwatersrand in Johannesburg, South Africa, and colleagues wrote. “The high estimated efficacy of male condoms in reducing HSV-2 transmission has important public health implications for this highly prevalent sexually transmitted infection for which there is not an effective preventive HSV-2 vaccine.”
The researchers evaluated 911 HSV-2 and HIV-1 serodiscordant couples from East and Southeastern Africa who were enrolled in the Partners in Prevention HSV-2/HIV 1 Transmission Study. One partner in each couple was coinfected with HSV-2/HIV-1 (799 men); the other partner was HSV-HIV-1 seronegative. Participants were followed for a median of 18 months. The researchers evaluated the per-act rates of HSV-2 transmission with and without condoms, and utilized infectivity models to determine the effect of condom use on HSV-2 transmission.
HSV-2 transmission occurred in 68 couples, 17 of which included susceptible women and 51 with susceptible men.
The risk for HSV-2 transmission from men to women was 28.5 transmissions per 1,000 unprotected sex acts (95% CI, 10.8-74.1) and 1.3 male-to-female transmissions per 1,000 protected acts (95% CI, 0.4 to 4.5), yielding a 96% reduction in HSV-2 transmission with male condom use (95% CI, 84%-99%).
The risk for transmission from women to men was 1.7 transmissions per 1,000 unprotected sex acts (95% CI, 0.6-4.4) and 0.6 per 1,000 protected sex acts (95% CI, 0.2-1.7), or a 65% reduction in HSV-2 transmission with male condom use (95% CI, –5% to 88%).
According to the researchers, this difference in condom efficacy (P = .014) may be related to differences in the ability of condoms to minimize contact with the anatomic locations of virus shedding.
“Our findings suggest that male condoms are very effective in preventing HSV-2 transmission from men to women and are likely to provide some protection for susceptible men as well,” Rees and colleagues concluded. “The mechanism of this sex difference may be related to the differing ability of the condom to diminish contact with anatomic sites of viral replication, as men tend to shed HSV on the penile shaft, whereas HSV-2 shedding in women occurs on the wider area of the vulva and perineum.” – by Jen Byrne
Disclosure: Rees reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.